In the past, persons in the art have recognized the need to provide tamper resistant closures for medicine and food containers. For example, Knapp, U.S. Pat. No. 3,158,278, discloses one form of tamper resistant closure. In Knapp's system, a metal cap having a two part skirt connected by bridges is placed on a container having a plurality of longitudinal ridges spaced along the neck, and axial threading positioned thereabove. The cap is crimped onto the closure, so that it conforms to the threading and the ridges. When twisting forces are applied to open the cap, the ridges prevent the lower part of the skirt from rotating. The twisting forces eventually cause the bridges to break, providing evidence of tampering.
A similar system is disclosed by Keeler, U.S. Pat. No. 4,153,174. A molded plastic cap having an upper skirt featuring threading is connected to a lower skirt having at least one U-shaped break-away tab molded therein. The tab engages the lower edge of a tamper molded on the container beneath the threading. When the cap is twisted, the break-away tab presses against the ring and, as the forces increase, breaks away, providing evidence of tampering.
In another system disclosed by Amberg, U.S. Pat. No. 3,951,292, a bottle having a long neck is provided with a conventional bottle cap. A framed thermoplastic overcap is provided having a plurality of longitudinal pleats and an axial scoring line placed such that it aligns with the space defined by the end of the cap and the beginning of a lip provided on the bottle neck. The overcap is glued in place using an adhesive and is torn along the score line when the bottle cap is twisted open. The broken overcap provides evidence of tampering.
Each of the foregoing systems, however, has attendant disadvantages. The Knapp systems requires special machinery to crimp the metal caps in place, which is expensive and not entirely suitable for all types of containers. Moreover, the required metal caps themselves are much more expensive than molded plastic caps, and are less adaptable to special features such as pouring spouts. Finally, such metal caps may have, after opening, exposed sharp edges, a possible accident hazard.
The Keeler system uses a breakway mechanism which could possibly slip over the threading on the bottleneck, thereby defeating the tamper evident mechanism. The Amberg system seems adapted especially for use in glass bottles having long necks, and seems illsuited for use in wide-mouth containers having very short necks.
Finally, each the foregoing existing closure systems require a fair amount of force to open, and would therefore be difficult for an elderly or arthritic person or a young child to easily operate.
Accordingly, it is an object of the present invention to provide a tamper resistant closure which is useful with a wide variety of containers, closures, and materials. It is also an object of the invention to provide a tamper resistant closure which may be easily opened by cutting or peeling away a protective sleeve.
It is another object of the invention to provide a tamper resistant closure using inexpensive materials which can be easily and economically manufactured. It is yet another object of the invention to provide a tamper resistant closure which consistently provides obvious evidence of tampering, and which cannot easily be defeated.
Another object is to provide a bottle including projecting teeth engaging a shrinkable sleeve wherein the cooperation of the shrunk sleeving and the projecting teeth provides tamper resistance. A further object is to provide such a bottle and sleeve wherein the interaction between the teeth and the sleeve when the sleeve is forcibly rotated relative to the teeth during tampering, irreversibly and visibly affects the sleeve, indicating tampering.
A further object is to provide a shrink wrap sleeve which has longitudinal areas of relative mechanical weakness. A related object is to provide a bottle with projecting teeth wherein the longitudinal weak areas cooperate with the teeth during tampering, resulting in mechanical failure and tearing of the sleeve proximate to the teeth, thereby providing an indicator of tampering. A still further object is to provide a tamper resistant closure system in which such longitudinal areas of weakness also function to provide a tear-away tab portion for easy removal of the protective sleeve.
These and other advantages, objects, and features at the present invention will become apparent in light of the present specification and accompanying drawings.